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Abstract:

Provided is a resource management system in a communication system
including a plurality of systems having no right to use a first frequency
band. The resource management system includes: a coexistence manager (CM)
configured to manage the plurality of systems for the purpose of
coexistence and frequency sharing of the plurality of systems in a
frequency band available for the plurality of systems, when the available
frequency band is detected in the first frequency band; a coexistence
enabler (CE) configured to transmit and receive information of the
plurality of systems and information of the CM; and a coexistence
discovery and information server (CDIS) configured to support the CM to
control the plurality of systems. The CM performs channel classification
for the first frequency band based on channel information of the
available frequency band, and allocates operating channels to the
plurality of systems.

Claims:

1. A resource management system in a communication system including a
plurality of systems having no right to use a first frequency band, the
resource management system comprising: a coexistence manager (CM)
configured to manage the plurality of systems for the purpose of
coexistence and frequency sharing of the plurality of systems in a
frequency band available for the plurality of systems, when the available
frequency band is detected in the first frequency band; a coexistence
enabler (CE) configured to transmit and receive information of the
plurality of systems and information of the CM; and a coexistence
discovery and information server (CDIS) configured to support the CM to
control the plurality of systems, wherein the CM performs channel
classification for the first frequency band based on channel information
of the available frequency band, and allocates operating channels to the
plurality of systems.

2. The resource management system of claim 1, further comprising a TV
white space database (TV WSDB) configured to provide channel information
of the available frequency band, wherein the CM transmits a request
message to the TVWS DB and the CE so as to acquire the channel
information of the available frequency band.

3. The resource management system of claim 2, wherein the CM receives a
response message including the channel information of the available
frequency band from the TVWS DB and the CE in response to the request
message.

4. The resource management system of claim 3, wherein the request message
and the response message comprise a header, a payload, and a data type.

5. The resource management system of claim 1, wherein when the plurality
of systems do not provide a service requested by users at the allocated
operating channels while providing the service to the users at the
allocated operating channels through the coexistence and frequency
sharing, the plurality of systems transmit an event message requesting
allocation of new operating channels to the CM.

6. The resource management system of claim 5, wherein the event message
comprises a header, a payload, and a data type.

7. The resource management system of claim 5, wherein the CM receives the
event message to check the channel classification of the first frequency
band, and allocates available channels and restricted channels in the
channel classification of the first frequency band as the new operating
channels.

8. The resource management system of claim 1, wherein the CM classifies
the first frequency band into operating channels, coexistent channels,
available channels, protected channels, restricted channels, disallowed
channels, allowed channels, and unclassified channels through the channel
classification.

9. The resource management system of claim 8, wherein the CM allocates
the operating channels of the plurality of systems from the available
channels and the restricted channels.

10. The resource management system of claim 1, wherein the CM updates the
channel classification of the first frequency band in response to the
operating channel allocation for the plurality of systems, and transmits
the updated channel classification information to the CDIS and neighbor
CMs.

11. The resource management system of claim 10, wherein the CM comprises
the channel classification information, and transmits a message
containing a header, a payload, and a data type to the CDIS and the
neighbor CMs.

12. The resource management system of claim 1, wherein the CM allocates
the operating channels of the plurality of systems from the available
frequency band through individual TV channel allocation.

13. The resource management system of claim 1, wherein the CM allocates
the operating channels of the plurality of systems from the available
frequency band through shared TV channel allocation between similar and
dissimilar devices.

14. A method for managing resources of a first frequency band in a
communication system including a plurality of systems having no right to
use the first frequency band, the method comprising: acquiring channel
information of a frequency band available for the plurality of systems
from a TVWS BD providing channel information of the available frequency
band, when the available frequency band is detected in the first
frequency band; performing channel classification for the first frequency
band based on the channel information of the available frequency band;
and allocating operating channels of the plurality of systems from the
channel classification for the first frequency band.

15. The method of claim 14, further comprising receiving a message
requesting allocation of new operating channels from the plurality of
systems, when the plurality of systems do not provide services requested
by users at the allocated operating channels while providing the services
to the users at the allocated operating channels through coexistence and
frequency sharing.

16. The method of claim 15, wherein, in said allocating the operating
channels of the plurality of systems from the channel classification for
the first frequency band, the channel classification for the first
frequency band is checked in response to the allocation request of the
new operating channels, and available channels and restricted channels in
the channel classification for the first frequency band are allocated as
the new operating channels.

17. The method of claim 14, wherein, in said performing the channel
classification for the first frequency band based on the channel
information of the available frequency band, the first frequency band is
classified into operating channels, coexistent channels, available
channels, protected channels, restricted channels, disallowed channels,
allowed channels, and unclassified channels.

18. The method of claim 17, wherein, in said allocating the operating
channels of the plurality of systems from the channel classification for
the first frequency band, the operating channels of the plurality of
systems are allocated from the available channels and the restricted
channels.

19. The method of claim 14, further comprising updating the channel
classification for the first frequency band in response to the operating
channel allocation for the plurality of systems, and transmitting the
updated channel classification information.

20. The method of claim 14, wherein, in said allocating the operating
channels of the plurality of systems from the channel classification for
the first frequency band, the operating channels of the plurality of
channels are allocated through one method of individual TV channel
allocation and shared TV channel allocation between similar and
dissimilar devices.

Description:

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] The present application claims priority of Korean Patent
Application Nos. 10-2010-0111431 and 10-2011-0116296, filed on Nov. 10,
2010, and Nov. 9, 2011, respectively, which are incorporated herein by
reference in their entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] Exemplary embodiments of the present invention relate to a
communication system; and, more particularly, to a resource management
system and method for managing a plurality of frequency resources to be
shared in a communication system.

[0004] 2. Description of Related Art

[0005] In current communication systems, studies have been actively
conducted to provide users with services which have various qualities of
service (hereinafter referred to as `QoS`) at a high transmission rate.
In the communication systems, studies have been actively conducted to
provide a large capacity service having various QoS requirements using
limited resources, e.g., frequency resources. In particular, with the
development of radio communication technologies and the introduction of
new radio communication services, it is necessary that the finite
frequency resources should be more efficiently used.

[0006] Methods for maximizing spectrum efficiency through the optimization
of a communication system, e.g., multi-access, coding, modulation,
information compression, etc. and minimizing interference with other
communication systems have been proposed as methods for improving the
usage efficiency of the finite frequency resources in the communication
system. There has been proposed a method for improving the usage
efficiency of the frequency resources by utilizing an available frequency
band in an already-used frequency band such as a TV band.

[0007] Here, the frequency sharing in an available frequency band in the
already-used frequency band such as the TV band should be performed by
utilizing the available frequency band without interfering with a primary
incumbent having a priority to use the TV band. Therefore, it is
important to check whether or not the primary incumbent uses the
frequency band in the TV band and then detect an available frequency
band. Furthermore, when there exist a plurality of different systems
intended to use the available frequency band detected in the TV band, a
problem occurs in coexistence for utilizing the available frequency band
due to a difference in communication method, e.g., radio access method
between the plurality of different systems.

[0008] In other words, in the current communication systems, when there
exist a plurality of different systems intended to use the available
frequency band detected in the TV band as described above, there is no
specific resource management method in which the plurality of different
systems efficiently use the detected available frequency band. In
particular, a specific method for efficiently utilizing the frequency
band when systems having different communication schemes coexist to use
the available frequency band has not been proposed.

[0009] Therefore, it is required to propose a resource management method
for detecting an available frequency band in an already-used frequency
band such as a TV band in a communication system and then efficiently
utilizing the detected available frequency band when a plurality of
different systems, e.g., a plurality of systems having different
communication schemes coexist.

SUMMARY OF THE INVENTION

[0010] An embodiment of the present invention is directed to a resource
management system and method in a communication system.

[0011] Another embodiment of the present invention is directed to a
resource management system and method which enables a plurality of
systems to effectively use a frequency band available in an already-used
frequency band in a communication system, through coexistence.

[0012] Another embodiment of the present invention is directed to a
resource management system and method which manages frequency resources
such that a plurality of systems coexist in a communication system and
uses an available frequency band in a TV band.

[0013] Another embodiment of the present invention is directed to a
resource management system and method which manages frequency resources
such that an available frequency band of a TV band is allocated to a
plurality of systems according to a channel allocation request of the
plurality of systems coexisting in a communication system.

[0014] Other objects and advantages of the present invention can be
understood by the following description, and become apparent with
reference to the embodiments of the present invention. Also, it is
obvious to those skilled in the art to which the present invention
pertains that the objects and advantages of the present invention can be
realized by the means as claimed and combinations thereof.

[0015] In accordance with an embodiment of the present invention, there is
provided a resource management system in a communication system including
a plurality of systems having no right to use a first frequency band. The
resource management system includes: a coexistence manager (CM)
configured to manage the plurality of systems for the purpose of
coexistence and frequency sharing of the plurality of systems in a
frequency band available for the plurality of systems, when the available
frequency band is detected in the first frequency band; a coexistence
enabler (CE) configured to transmit and receive information of the
plurality of systems and information of the CM; and a coexistence
discovery and information server (CDIS) configured to support the CM to
control the plurality of systems. The CM performs channel classification
for the first frequency band based on channel information of the
available frequency band, and allocates operating channels to the
plurality of systems.

[0016] In accordance with another embodiment of the present invention,
there is provided a method for managing resources of a first frequency
band in a communication system including a plurality of systems having no
right to use the first frequency band. The method includes: acquiring
channel information of a frequency band available for the plurality of
systems from a TVWS BD providing channel information of the available
frequency band, when the available frequency band is detected in the
first frequency band; performing channel classification for the first
frequency band based on the channel information of the available
frequency band; and allocating operating channels of the plurality of
systems from the channel classification for the first frequency band.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 schematically illustrates the architecture of a resource
management system in a communication system in accordance with an
embodiment of the present invention.

[0018]FIG. 2 is a flow chart showing a channel allocation operation of
the resource management system in a communication system in accordance
with the embodiment of the present invention.

[0019]FIG. 3 is a diagram explaining channel classification of the
resource management system in the communication system in accordance with
the embodiment of the present invention.

DESCRIPTION OF SPECIFIC EMBODIMENTS

[0020] Exemplary embodiments of the present invention will be described
below in more detail with reference to the accompanying drawings. The
present invention may, however, be embodied in different forms and should
not be construed as limited to the embodiments set forth herein. Rather,
these embodiments are provided so that this disclosure will be thorough
and complete, and will fully convey the scope of the present invention to
those skilled in the art. Throughout the disclosure, like reference
numerals refer to like parts throughout the various figures and
embodiments of the present invention.

[0021] The exemplary embodiments of the present invention propose a
resource management system and method for efficiently detecting and
utilizing an available frequency band, e.g., a white space (hereinafter,
referred to as `WS`) in an already-used frequency band such as a TV band
in a communication system, e.g., a cognitive radio (hereinafter, referred
to as `CR`) system, a system based on IEEE 802.19, or a system based on
IEEE 802.22. In the embodiments of the present invention, the CR system,
the system based on IEEE 802.19, and the system based on IEEE 802.22 is
described as an example. However, the resource management system and
method in accordance with the embodiments of the present invention may be
applied to other communication systems.

[0022] In the embodiments of the present invention, there is proposed a
resource management system and method for efficiently using frequency
bands available in a TV band in a communication system where a plurality
of different systems coexist. In the embodiments of the present
invention, objects of the resource management system for sharing
available frequency bands coexist in the communication system, and a
plurality of systems, or particularly, systems having different
communication methods, e.g., wireless access systems coexist in such a
manner that the systems share an available frequency band in an
already-used frequency band such as a TV band. Accordingly, utilization
efficiency of frequency resources is improved.

[0023] In the embodiments of the present invention, the resource
management system for coexistence and frequency sharing of the plurality
of different systems in the communication system shares an available
frequency band, thereby improving the usage efficiency of limited
frequency resources. In the embodiments of the present invention,
frequencies in the available frequency band are shared in an already-used
frequency band such as a TV band. At this time, the available frequency
band should be used without interfering with a primary incumbent having a
priority for the TV band. Therefore, the resource management system
checks whether or not the primary incumbent uses the frequency band in
the TV band and detects an available frequency band, and the plurality of
different systems intended to use the available frequency band detected
from the TV band select and use operating channels in the detected
available frequency band through coexistence and frequency sharing.

[0024] In other words, in the resource management system for coexistence
and frequency sharing between the plurality of different systems in the
communication system, predetermined objects for effective coexistence
select operating channels in the WS. At this time, in order to
effectively select operating channels in the WS, the resource management
system classifies available channels in the WS and allocates the
channels. Hereinafter, the resource management system in a communication
system in accordance with the embodiment of the present invention will be
described in more detail with reference to FIG. 1.

[0025] FIG. 1 schematically illustrates the architecture of the resource
management system in the communication system in accordance with the
embodiment of the present invention.

[0026] Referring to FIG. 1, when a plurality of different systems intend
to use an available frequency band in an already-used frequency band such
as a TV band, the resource management system includes sharing devices
intended to use the available frequency band through frequency sharing in
the plurality of different systems, e.g., TV band devices (hereinafter,
referred to as `TVBD`), e.g., a TVBD1 140 and a TVBD2 160, coexistence
managers (hereinafter, referred to as `CM`), e.g., a CM1 120 and a CM2
130, which manage the TVBDs 140 and 160 so as to improve the frequency
sharing efficiency between the TVBDs 140 and 160, coexistence enablers
(hereinafter, referred to as `CE`), e.g., a CE1 140 and a CE2 170 which
are included in the TVBDs 140 and 160 or independently positioned and
serve as a path between the TVBDs 140 and 160 and the CMs 120 and 130, a
server, e.g., a coexistence discovery and information server
(hereinafter, referred to as a `CIDS`) 110, which supports the CEs 140
and 170 and the CMs 120 and 130 to control the TVBDs 140 and 160, and a
TV white space database (hereinafter, referred to as a `TVWS DB`) 180
which provides channel information on an available band in the TV band,
that is, a TVWS.

[0027] When a primary incumbent (hereinafter, referred to as `primary
system`) having a priority to use the TV band does not use a
predetermined frequency band in the TV band, the TVBDs 140 and 160 may
indicate devices of a plurality of different systems (hereinafter,
referred to as `secondary systems`) which have no priority to use the TV
band and intend to detect and use a predetermined frequency band in the
TV band as an available frequency band. Here, the TVBDs 140 and 160 share
the predetermined frequency band through coexistence and frequency
sharing, in order to more efficiently use limited frequency resources.
That is, the TVBDs 140 and 160 transmit and receive data through channels
allocated from the TVWS.

[0028] As described above, the CEs 150 and 170 are independently
positioned in the TVBDs 140 and 160, respectively, and transmit and
receive information of the TVBDs 140 and 160 and information of the CMs
120 and 130. In the embodiment of the present invention, the following
descriptions will be focused on a case which the CEs 150 and 170
independently exist in the TVBDs 140 and 160, for convenience of
explanation. However, the CEs 150 and 170 may be included in the TVBDs
140 and 160 or the CMs 120 and 130.

[0029] The CEs 150 and 170 extract context information related to the
TVBDs 140 and 160, which is requested by the CMs 120 and 130, from the
TVBD 140 and 160, and transmit the extracted information to the CMs 120
and 130. The context information includes a wireless access method,
transmit power, spectrum sensing threshold values, and locations of the
TVBDs 140 and 160. That is, the CEs 150 and 170 acquire communication
related information of the respective systems as the context information
of the secondary systems and transmit the acquired information to the CMs
120 and 130.

[0030] The CEs 150 and 170 receive requests of the CMs 120 and 130 for
managing the TVBDs 140 and 160, e.g., requests for the context
information and configuration of the TVBDs 140 and 160. The CEs 150 and
170 update the context information of the TVBDs 140 and 160 according to
the requests, and reset the configuration of the TVBDs 140 and 160, i.e.,
reconfigure the TVBDs 140 and 160. In other words, the CEs 150 and 170
receive changed information of the context information, i.e., event
information of the TVBDs 140 and 160 as a request for the context
information of the TVBDs 140 and 160, and update the context information
of the TVBDs 140 and 160 according to the event information. In addition,
the CEs 150 and 170 receive information related to the reconfiguration of
the TVBDs 140 and 160 as a request for the configuration of the TVBDs 140
and 160, and reset the configuration of the TVBDs 140 and 160 according
to the reconfiguration information, i.e., reconfigures the TVBDs 140 and
160 according to the reconfiguration information.

[0031] The CMs 120 and 130 determine operating frequency allocation,
transmit power allocation, and transmit time allocation, in order to
improve the frequency sharing efficiency between the TVBDs 140 and 160.
That is, the CMs 120 and 130 perform the operating frequency allocation,
the transmit power allocation, and the transmit time allocation for the
TVBDs 140 and 160 in the available frequency band, in order to improve
the frequency sharing efficiency between the TVBDs 140 and 160 with
respect to the available frequency band in the above-described TV band.

[0032] In order to more efficiently improve the frequency sharing
efficiency between the TVBDs 140 and 160, the CMs 120 and 130 perform the
operating frequency allocation, the transmit power allocation, and the
transmit time allocation for the corresponding TVBDs in the available
frequency band by transmitting and receiving information to and from CMs
of TVBDs which do not correspond thereto, e.g., neighbor CMs, for
example, transmitting and receiving the context information and the event
information of the TVBDs. At this time, the CMs 120 and 130 acquire the
context and event information of the TVBDs which do not correspond
thereto by directly transmitting and receiving the information to and
from other CMs, e.g., neighbor CMs or by transmitting and receiving the
information to and from other CMs through the CDIS 110. In addition, the
CMs 120 and 130 acquire information on spectrum use in the primary
system, i.e., channel information on available channels in the TV band
through an external DB, e.g., the TVWS DB 180 or request other CMs to
reconfigure the TVBDs corresponding thereto.

[0033] As described above, the CDIS 110 supports a control operation of
the CMs 120 and 130 for frequency sharing of the TVBDs 140 and 160 with
respect to the available frequency band in the TV band. That is, the CDIS
110 receives the context and event information of the TVBDs 140 and 160
from the CMs 120 and 130 and stores the received context and event
information. According to requests of the CMs 120 and 130, the CDIS 110
transmits the context and event information of the TVBDs 140 and 160 to
the CMs 120 and 130. In addition, the CDIS 110 acquires the information
on the spectrum use in the primary system, that is, the channel
information on the available channels in the TV band through an external
DB, e.g., the TVWS DB 180, and stores the acquired information.

[0034] The TVWS DB 180 provides the channel information on the available
channels in the TVWS, e.g., the shared channel information to the CMs 120
and 130. The channel information is provided only to TVBDs which are
registered in the TVWS DB 180 and of which the identification numbers are
authenticated.

[0035] The resource management system in the communication system in
accordance with the embodiment of the present invention includes the TVWS
DB 180, the CDIS 110, the CMs 120 and 130, and the CEs 140 and 170 such
that the secondary systems share and use the available frequency band in
the frequency band used by the primary system, such as the TV band, that
is, the TVBDs 140 and 160 coexist and share the frequency band. Here, the
TVBDs 140 and 160 may include a base station (hereinafter, referred to as
a `BS`), an access point (hereinafter, referred to as an `AP`), a service
access point (hereinafter, referred to as a `SAP`), and a terminal as the
devices of the secondary systems to share and use the available frequency
band as described above. Furthermore, the secondary systems may include
systems having different communication methods, e.g., systems based on
IEEE 802.19, IEEE 802.22 and the like as the plurality of different
systems to share the available frequency band as described above.

[0036] The resource management system in the communication system in
accordance with the embodiment of the present invention classifies
available channels in the TV band such that the TVBDs 140 and 160 coexist
and share the available frequency band in the already-used frequency
band, allocates the available channels such that the TVBDs 140 and 160
use the allocated available channels, and then selects operating channels
in the TVWS. That is, in the resource management system for the
coexistence and frequency sharing between the plurality of different
systems, predetermined objects, e.g., the CMs 120 and 130 select the
operating channels in the TVWS in order for effective coexistence. At
this time, the resource management system classifies and allocates
available channels in the TVWS so as to effectively select the operating
channels in the TVWS.

[0037] Here, the number of systems intended to coexist through frequency
sharing is larger than the number of channels available in a
corresponding region when the plurality of systems coexist. Therefore,
when selecting the operating channels of the plurality of systems for
coexistence, e.g., TVBDs, the frequency management system
selects/allocates the operating channels using individual TV channel
allocation, shared TV channel allocation between same/similar TVBDs, and
shared TV channel allocation between dissimilar TVBDs.

[0038] The individual TV channel allocation is where different TV channels
are adaptively allocated to the respective TVBDs. Accordingly, since
spectrum overlapping between the TVBDs does not occur, the individual TV
channel allocation does not cause interference, and allocates proper TV
channels to the TVBDs so as to support the coexistence of the TVBDs. The
shared TV channel allocation between same/similar TVBDs is where two or
more same/similar TVBDs, e.g., TVBDs using the same wireless access
method share the same TV channels. At this time, two or more TV channels
may be allocated to and shared by the same/similar TVBDs. Here, when the
same/similar TVBDs share the TV channels, a self-coexistence algorithm is
used to reduce interference occurring between the same/similar TVBDs. For
example, the same/similar TVBDs, that is, two or more IEEE 802.22 systems
as the same/similar systems perform channel sharing between IEEE 802.11
systems using the self-coexistence algorithm such as an on-demand frame
contention (hereinafter, referred to as `ODFC`). Furthermore, the shared
TV channel allocation between dissimilar TVBDs is where two or more
dissimilar TVBDs, that is, TVBDs using different wireless access methods
share the same TV channels. In the shared TV channel allocation between
dissimilar TVBDs, a coexistence algorithm between dissimilar systems is
used to minimize interference occurring between dissimilar TVBDs.

[0039] Furthermore, the resource management system selects the operating
channels which are to be used by the CM, in order for the coexistence and
frequency sharing of a plurality of systems. That is, as described above,
the resource management system classifies available channels in the TVWS,
and then allocates channels from the classified available channels to
select the operating channels. At this time, the resource management
system classifies idle channels, i.e., available channels in the TV band
using registered TVBD information, and allocates the operating channels
to the plurality of systems from the classified channels. Then, the
operation in which the CM of the resource management system in the
communication system in accordance with the embodiment of the present
invention allocates the available channels in the TV band will be
described in more detail.

[0040]FIG. 2 is a flow chart showing the channel allocation operation of
the resource management system in the communication system in accordance
with the embodiment of the present invention. FIG. 2 schematically shows
the channel allocation operation of the CM, when TVBDs request channel
allocation in the TVWS, or particularly, when the TVBDs request the CM to
allocate new operating channels because various QoS requirements
requested by users are not satisfied while services are provided to the
users through the operating channels allocated by the CM of the resource
management system. Furthermore, the resource management system allocates
available channels as operating channels to the TVBDs according to the
type of the TVBDs and whether or not neighbor CMs use the channels in the
TVWS. Therefore, the resource management system performs the channel
classification in the TVWS and then performs the operating channel
allocation, in order for effective coexistence and frequency sharing
between the plurality of systems.

[0041] Referring to FIG. 2, the CM of the resource management system
receives an allocation request message for operating channels from the
plurality of systems which intend to provide services to users through
the coexistence and frequency sharing in the TVWS, i.e., the TVBDs, at
step S210. Here, the CM receives messages requesting the allocation of
new operating channels from TVBDs which do not satisfy QoS requirements
requested by users, while providing services to the users using the
operating channels allocated from the CM.

[0042] Then, at step S220, the CM checks the channel classification of the
TVWS in the TV band. The TV band is classified into operating channels,
coexistent channels, available channels, protected channels, restricted
channels, disallowed channels, allowed channels, unclassified channels
and so on. The CM checks the channel classification state for the TVWS in
the TV band at the step S220. The channel classification for the TVWS in
the TV band will be described in more detail with reference to FIG. 3.
Thus, the detailed descriptions thereof are omitted herein.

[0043] At step S230, the CM checks whether or not available channels exist
in the channel classification of the TV band. That is, the CM checks
whether or not channels which may be used by the TVBDs exist in the TV
band.

[0044] When it is checked as the result of the step S230 that the
available channels exist in the TV band, the CM allocates operating
channels to the TVBDs from the available channels of the TV band, at step
S240. Then, the CM updates the channel classification in the TV band in
response to the operating channel allocation for the TVBDs, and then
transmits the updated channel classification information to the CDIS and
neighbor CMs, at step S250.

[0045] Meanwhile, when it is checked as the result of the step S230 that
available channels do not exist in the TV band, the CM checks whether or
not restricted channels exist in the TV band, at step S260.

[0046] When it is checked as the result of the step S260 that the
restricted channels exist in the TV band, the CM checks whether or not
the existing restricted channels are available, at step S270. That is,
the CM checks whether or not the TVBDs may use the restricted channels in
the TV band through coexistence and frequency sharing. At this time, when
the restricted channels in the TV band are available, the CM allocates
operating channels to the TVBDs from the restricted channels in the TV
band, at step S240. Then, the CM updates the channel classification of
the TV band and transmits the updated channel classification information
to the CDIS and neighbor CMs, at step S250.

[0047] Meanwhile, when it is checked as the result of the step S260 that
the restricted channels do not exist in the TVWS or when it is checked as
the result of the step S270 that the restricted channels are not
available, the CM allocates operating channels to the TVBDs registered in
the CM in the TVWS by considering TVBDs causing adjacent frequency
interference with the TVBDs registered in the CM, i.e., TVBDs registered
in neighbor CMs, at step S280. Here, the CM allocates available channels
as the operating channels to the TVBDs according to the type of the TVBDs
and whether or not the channels are used by the neighbor CMs in the TVWS.
At this time, the CM sets an Initiate_Channel_Allocation flag to `1`, for
example, to allocate the available channels to the plurality of systems,
i.e., the TVBDs. Hereinafter, the classification of available channels in
the TV band in the communication system in accordance with the embodiment
of the present invention will be described in more detail with reference
to FIG. 3.

[0048]FIG. 3 is a diagram explaining the channel classification of the
resource management system in the communication system in accordance with
the embodiment of the present invention. Here, since the channel
allocation is decided according to the type of TVBDs and whether neighbor
CMs use channels or not in the TVWS, the resource management system
performs the channel classification of the TVWS for the TV band as shown
in FIG. 3, in order for effective coexistence and frequency sharing
between a plurality of systems.

[0049] Referring to FIG. 3, the CM of the resource management system
acquires information on available channels in the TV band, that is,
channel information of the TVWS from the TVWS DB, and classifies TV
channels 300 of the TV band, which the plurality of systems do not have a
right to use, into disallowed channels 310, available channels 320,
restricted channels 330, allowed channels 340, operating channels 325,
coexistent channels 327, protected channels 342, unclassified channels
344 and so on, based on the channel information. Here, the
above-described channel classification of the CM in the TV channels is
only an example, and the TV channels may be classified in various manners
according to the coexistence and frequency sharing of the plurality of
systems in the TVWS.

[0050] The operating channels 325 indicate a group of sub frequency
resources allocated to one system, i.e., one TVBD which shares the TV
channels 300 through coexistence and frequency sharing or a plurality of
systems, i.e., TVBDs which uses the same wireless access method. Here,
the sub frequency resources may be represented by channels as partial
frequency bands in the entire frequency band which may be used by the
primary incumbent, that is, the primary system. Furthermore, the
operating channels 325 are allocated from the available channels 320 and
the restricted channels 330 of the TV channels 300.

[0051] The coexistent channels 327 indicate a group of sub frequency
resources allocated to two or more systems, i.e., two or more TVBDs which
use the same wireless access method or different wireless access methods.
The coexistent channels 327 are allocated from the operating channels 325
of the TV channels 300.

[0052] The available channels 320 indicate a group of sub frequency
resources which may be allocated to one or more systems, i.e., one or
more TVBDs from the TV channels through coexistence and frequency
sharing, because they are not used locally or temporally by the primary
incumbent system, i.e., the primary system, and satisfy the channel
quality to a predefined level or more. That is, the available channels
320 indicate channels which may be used by a plurality of systems, i.e.,
TVBDs through the coexistence and frequency sharing, and are allocated
from the TV channels 330.

[0053] The protected channels 342 indicate a group of sub frequency
resources which are used by the primary incumbent system, i.e., the
primary system and cannot be allocated to a plurality of systems, i.e.,
TVBDs. That is, the protected channels 342 indicate channels which cannot
be used by the plurality of systems.

[0054] The restricted channels 330 indicate a group of sub frequency
resources which may be restrictively allocated to a plurality of system
from the TV channels 300 according to regulations related to the
frequency band. For example, since adjacent sub frequency resources are
used by the primary system, sub frequency resources which may be
restrictively allocated to the plurality of systems through coexistence
and frequency sharing are included in the restricted channels 300. Here,
adjacent sub frequency resources of an F-th sub frequency resource are
defined as an (F±1)-th sub frequency resource or an (F±2)-th sub
frequency resource. At this time, the sub frequency resources included in
the restricted channels 330 indicate frequency resources which are not
allocated to a plurality of systems, i.e., TVBDs. Furthermore, the sub
frequency resources of the restricted channels 330 are restrictively
allocated to the plurality of systems, because the corresponding
frequency band is allocated to the plurality of systems in a state where
the sub frequency resources of the corresponding frequency band use a low
power level which is positively discriminated from a power level used by
the primary system.

[0055] The disallowed channels 310 indicate a group of sub frequency
resources in the TV channels 300, which the plurality of systems are
forbidden to use according to the regulation related to the frequency
band, i.e., a group of sub frequency resources which must not be
allocated to the plurality of systems.

[0056] The unclassified channels 344 indicate a group of sub frequency
resources which do not correspond to the channel classification of the TV
channels 300 into the operating channels 325, the coexistent channels
327, the available channels 320, the restricted channels 330, the
protected channels 342, and the disallowed channels 310. That is, the
unclassified channels 344 indicate a group of sub frequency resources of
which the states are not identified, in the TV channels 300.

[0057] The CM of the resource management system in accordance with the
embodiment of the present invention transmits and receives messages
between the TVBDs and the TVWS DB, the CDIS, the neighbor CMs, and the
CEs registered in the CM, in order to classify the TV channels 300.
First, the CM acquires idle channel information, i.e., the channel
information of the TVWS from the CEs registered in the TVWS DB or the CM,
in order to perform the channel classification for the TVWS in the
above-described TV band. The CM transmits an AvailableChannel_Request
message or CM_AvailableChannel_Request message as a request message of
the channel information for acquiring such channel information to the CEs
registered in the TVWS DB or the CM.

[0058] Table 1 shows the header and the payload of the
AvailableChannel_Request message to request the channel information of
the TVWS. Furthermore, Table 2 shows the header and the payload of the CM
AvailableChannel_Request message to request the channel information of
the TVWS, and Table 3 shows the data type of the
CM_AvailableChannel_Request message.

[0059] Furthermore, as the CM transmits the AvailableChannel_Request
message or the CM_AvailableChannel_Request message to the CMs registered
in the TVWS DB or the CM in order to acquire the channel information of
the TVWS, the CM receives an AvailabeChannel_Response message or
AvailableChannel_Announcement message including the channel information
of the TVWS as a response message to the AvailableChannel_Request message
or the CM_AvailableChannel_Request message from the CEs registered in the
TVWS DB or the CM.

[0060] Table 4 shows the header and the payload of the
AvailableChannel_Response message including the channel information of
the TVWS, and Table 5 shows the data type of the
AvailableChannel_Response message. Furthermore, Table shows the header
and the payload of the AvailableChannel_Announcement message including
the channel information of the TVWS.

[0061] As such, the CM of the resource management system acquires the
channel information of the TVWS by transmitting and receiving the
AvailableChannel_Request message or CM AvailableChannel_Request message
to request the channel information of the TVWS and the
AvailableChannel_Response message or the AvailableChannel_Announcement
message including the channel information of the TVWS, and performs the
channel classification for the TVWS in the TV band as shown in FIG. 3
based on the acquired channel information of the TVWS, that is,
classifies the channels of the TV band. Furthermore, the CM allocates the
classified channels available in the TV band to the plurality of systems,
i.e., the TVBDs as the operating channels of the TVBDs through the
coexistence and frequency sharing.

[0062] That is, the CM of the resource management system performs the
channel classification of the TV band, and then allocates the channels
available in the TV band as the operating channels to the plurality of
systems, i.e., the TVBDs. The TVBDs provide communication services to
users at the operating channels allocated through the coexistence and
frequency sharing. At this time, when the TVBDs cannot provide
communication services satisfying QoS requirements requested by the
users, the TVBDs transmit an allocation request message requesting
allocation of new operating channels to the CM.

[0063] At this time, the TVBDs transmit an Event_Indication message or
Event_Confirm message to the CM as an event message announcing that an
event occurs to allocate new operating channels for satisfying the QoS
requirements requested by the users. That is, the TVBDs transmit the
Event_Indication message or Event_Confirm message to the CM, and request
the CM to allocate new operating channels in the TVWS. Table 7 shows the
header and the payload of the Event_Indication message, Table 8 shows the
data type of the Event_Indication message, and Table 9 shows the header
and the payload of the Event_Confirm message.

[0064] As such, the CM receives the Event_Indication message or the
Event_Confirm message from the TVBDs as the allocation request message to
request the allocation of new operating channels. Then, as described with
reference to FIG. 2, the CM allocates the operating channels to the TVBDs
from the channels available in the TV band, i.e., the available channels
or restricted channels of the TVWS. Furthermore, as described with
reference to FIG. 2, the CM updates the channel classification of the TV
band to reflect the operating channel allocation for the TVBDs into the
channel classification described with reference to FIG. 3, in response to
the allocation of the operating channels to the TVBDs from the TVWS.
Then, the CM transmits the updated channel classification information to
the CDIS and neighbor CMs.

[0065] That is, the CM transmits the updated channel classification
information to the CDIS and the neighbor CMs, after allocating the
operating channels to the TVBDs from the TVWS. At this time, the CM
transmits a ChannelClassification_Announcement message, a
NeighborInformation_Announcement message, or a
Neighborinformation_Confirm message as a message including the channel
classification information to the CDIS and the neighbor CMs. For example,
the CM transmits the ChannelClassification_Announcement message including
the channel classification information to the CDIS, and transmits the
NeighborInformation_Announcement message or the
NeighborInformation_Confirm message including the channel classification
information to the neighbor CMs.

[0066] Table 10 shows the header and the payload of the
ChannelClassification_Announcement message including the channel
classification information, and Table 11 shows the data type of the
ChannelClassification_Announcement message. Furthermore, Table 12 shows
the header and the payload of the NeighborInformation_Announcement
message including the channel classification information, and Table 13
shows the data type of the NeighborInformation_Ammuncement message.
Furthermore, Table 14 shows the header and the payload of the
NeighborInformation_Confirm message including the channel classification
information.

[0067] As such, the resource management system in accordance with the
embodiment of the present invention classifies the channels of the TVWS
in the TV band, in order to allocate the channels to the TVBDs registered
in the CM. The resource management system allocates the operating
channels of the TVBDs from the channels available among the classified
channels in the TV band, i.e., the available channels or restricted
channels. Furthermore, when the TVBDs do not provide communication
services satisfying the QoS requirements requested by the users while
providing the communication services to the users at the allocated
operating channels through the coexistence and frequency sharing, the
TVBD may request new operating channels. In this case, the CM checks the
classified channels in the TV band, and allocates new operating channels
to the TVBDs from the available channels or restricted channels.

[0068] At this time, the CM of the resource management system classifies
the channels of the TV band, and adaptively allocates the operating
channels to the TVBDs registered in the CM according to the number of
available channels in the TV band, i.e., the channel number of the TVWS
and whether or not the neighbor CMs use the TVWS. Accordingly, as the
operating channels are effectively allocated, the plurality of systems
effectively perform the coexistence and frequency sharing in the TVWS. In
particular, the CM of the resource management system classifies the
channels according to the channel characteristics and allocates the
channels available in the TV band as the operating channels. Therefore,
the CM may adaptively allocate the operating channels according to the
system environments of the plurality of systems. Furthermore, the CM of
the resource management system effectively allocates the channels
available in the TV band as the operating channels according to the
number of channels available in the TVWS and the number of neighbor
systems, i.e., neighbor CMs, in order to adaptively allocate the
operating channels according to the system environments of the plurality
of systems.

[0069] In accordance with the embodiments of the present invention, the
resource management system and method manages frequency resources such
that a plurality of systems use a frequency band available in an
already-used frequency band such as a TV band through coexistence in a
communication system. Therefore, limited frequency resources may be more
effectively used to improve the usage efficiency of the frequency
resources.

[0070] While the present invention has been described with respect to the
specific embodiments, it will be apparent to those skilled in the art
that various changes and modifications may be made without departing from
the spirit and scope of the invention as defined in the following claims.

Patent applications by Dong-Hun Lee, Daejeon KR

Patent applications by Electronics and Telecommunications Research Institute